Rather than naysay your efforts, I prefer to support. pg has opened up YC to people without ideas, so contrary to other comments here, I don't think you're violating the spirit of YC to request an interview without an idea. But your open-ended way of asking might give pg too much to think about. So that could be a reason why he hasn't got back to you yet.
One idea: pg wants to invest in more entrepreneurs who don't have ideas yet, and in some cases, perhaps even people without much history of success on paper. Applicants like yourselves need ideas to build. Create a system that makes it easy for YC's problems to be discovered by applicants, so applicants can use these problems as product ideas. Another tip: think beyond YC's problems to the problems of YC companies. The problems of YC companies are also YC's problems.
Another idea. I read that YC has trouble scaling their demo days each year. One article quoted a guy saying that the growing lunch line is actually one of Demo Day's bigger problems. Make YC Demo Day food service better for guests. Or instead, make it easier for YC to coordinate. I'm sure pg doesn't like thinking about it.
One idea: pg wants to invest in more entrepreneurs who don't have ideas yet, and in some cases, perhaps even people without much history of success on paper. Applicants like yourselves need ideas to build. Create a system that makes it easy for YC's problems to be discovered by applicants, so applicants can use these problems as product ideas. Another tip: think beyond YC's problems to the problems of YC companies. The problems of YC companies are also YC's problems.
Another idea. I read that YC has trouble scaling their demo days each year. One article quoted a guy saying that the growing lunch line is actually one of Demo Day's bigger problems. Make YC Demo Day food service better for guests. Or instead, make it easier for YC to coordinate. I'm sure pg doesn't like thinking about it.